/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.aliyun.oss.common.comm.io;

import static com.aliyun.oss.common.utils.LoggerUtils.logException;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.http.entity.AbstractHttpEntity;
import org.apache.http.entity.BasicHttpEntity;
import org.apache.http.entity.ContentType;
import org.apache.http.util.Args;

import com.aliyun.oss.common.comm.ServiceClient;
import com.aliyun.oss.common.utils.HttpHeaders;

/**
 * A repeatable HTTP entity that obtains its content from an non-auto-close 
 * {@link ReleasableInputStreamEntity} and sends its content using chunked encoding.
 */
public class ChunkedInputStreamEntity extends BasicHttpEntity {

	private boolean firstAttempt = true;
	private ReleasableInputStreamEntity notClosableRequestEntity;
    private InputStream content;

    public ChunkedInputStreamEntity(ServiceClient.Request request) {
    	setChunked(true);
    	
        long contentLength = -1;
        try {
            String contentLengthString = request.getHeaders().get(HttpHeaders.CONTENT_LENGTH);
            if (contentLengthString != null) {
                contentLength = Long.parseLong(contentLengthString);
            }
        } catch (NumberFormatException nfe) {
        	logException("Unable to parse content length from request.", nfe);
        }

        String contentType = request.getHeaders().get(HttpHeaders.CONTENT_TYPE);

        notClosableRequestEntity = new ReleasableInputStreamEntity(request.getContent(), contentLength);
        notClosableRequestEntity.setCloseDisabled(true);
        notClosableRequestEntity.setContentType(contentType);
        content = request.getContent();

        setContent(content);
        setContentType(contentType);
        setContentLength(contentLength);
    }

    @Override
	public boolean isChunked() {
    	return true;
	}

    @Override
    public boolean isRepeatable() {
        return content.markSupported() || notClosableRequestEntity.isRepeatable();
    }

    @Override
    public void writeTo(OutputStream output) throws IOException {
        if (!firstAttempt && isRepeatable()) 
        	content.reset();

        firstAttempt = false;
        notClosableRequestEntity.writeTo(output);
    }
	
    /**
     * A releaseable HTTP entity that can control its inner inputstream's auto-close functionality on/off,
     * and it will try to close its inner inputstream by default when the inputstream reaches EOF.
     */
	public static class ReleasableInputStreamEntity extends AbstractHttpEntity implements Releasable {
		
	    private final InputStream content;
	    private final long length;
	    
	    private boolean closeDisabled;

	    public ReleasableInputStreamEntity(final InputStream instream) {
	        this(instream, -1);
	    }

	    public ReleasableInputStreamEntity(final InputStream instream, final long length) {
	        this(instream, length, null);
	    }

	    public ReleasableInputStreamEntity(final InputStream instream, final ContentType contentType) {
	        this(instream, -1, contentType);
	    }

	    public ReleasableInputStreamEntity(final InputStream instream, final long length, final ContentType contentType) {
	        super();
	        this.content = Args.notNull(instream, "Source input stream");
	        this.length = length;
	        if (contentType != null) {
	            setContentType(contentType.toString());
	        }
	        closeDisabled = false;
	    }

	    @Override
	    public boolean isRepeatable() {
	        return this.content.markSupported();
	    }

	    @Override
	    public long getContentLength() {
	        return this.length;
	    }

	    @Override
	    public InputStream getContent() throws IOException {
	        return this.content;
	    }

	    @Override
	    public void writeTo(final OutputStream outstream) throws IOException {
	        Args.notNull(outstream, "Output stream");
	        final InputStream instream = this.content;
	        try {
	            final byte[] buffer = new byte[OUTPUT_BUFFER_SIZE];
	            int l;
	            if (this.length < 0) {
	                // consume until EOF
	                while ((l = instream.read(buffer)) != -1) {
	                    outstream.write(buffer, 0, l);
	                }
	            } else {
	                // consume no more than length
	                long remaining = this.length;
	                while (remaining > 0) {
	                    l = instream.read(buffer, 0, (int)Math.min(OUTPUT_BUFFER_SIZE, remaining));
	                    if (l == -1) {
	                        break;
	                    }
	                    outstream.write(buffer, 0, l);
	                    remaining -= l;
	                }
	            }
	        } finally {
	            close();
	        }
	    }

	    @Override
	    public boolean isStreaming() {
	        return true;
	    }
	    
	    public void close() {
			if (!closeDisabled)
				doRelease();
		}

		@Override
		public void release() {
			doRelease();
		}
		
		private void doRelease() {
			try {
	            this.content.close();
	        } catch (Exception ex) {
	            logException("Unexpected io exception when trying to close input stream", ex);
	        }
		}

		public boolean isCloseDisabled() {
			return closeDisabled;
		}

		public void setCloseDisabled(boolean closeDisabled) {
			this.closeDisabled = closeDisabled;
		}
	}
}
